The stock is already up 26% this year. SpaceX has been a remarkable success over the last 15 years. It brought the space flight industry in the United States -- really, around the world -- back to life and inspired plenty of copycats along the way. The age of commercial space flight is upon us and set to grow like gangbusters over the next 10 to 20 years. By 2050, the United Nations believes the space economy could be worth $3 trillion. Industry experts believe that SpaceX has a de facto monopoly on commerc ...